Drier for photographic prints



Dec. 17, 1929. A. J. CUNNINGHAM 1,739,505

DRIER FOR iHOTOGRAPHIC PRINTS Filed May 4. 1926 4 Sheets-Sheet 1 BY 4 v v ATTORNEY 1929. A. J. CUNNINGHAM 1,739,505

DRIER FOR PHOTOGRAPHIC PRINTS 4 Sheets-Sheet 2 Filed May 4, 1926 'INVENTOR flmm/rwmv Dec. 17, 1929.

A. .I CUNNINGHAM DRIER FOR IfHOTOGRAPHIC PRINTS Filed May 4, 1926 4 Sheets-Sheet 3 ATTORNEY 1929- A. J. CUNNINGHAM 1,739,505

DRIER FOR PHOTOGRAPHIC PRINTS Filed May 4, 1926 4 Sheets-Sheet 4 E HYVEN 20R Patented Dec. 17, 1929 UNITED STATES PATENT OFFICE Damn ron'rrmtroennrrrro rnnv'rs Application filed May 4, 1926. Serial n 105,627.

This invention relates to vdriers for photo.- graphic prints.

An object of the invention is ,to provide an improved method and means for handling and drying prints, whereby the drying is accomplished more'quickly and uniformly as to each print than heretofore. w

Another object is to provide an improved method and means for drying a plurality of groups of prints, and to insure drying of all the prints substantially at the same rate, whereby the method and means may be operated continuously and new groups of prints may be subjected to the drying action at uniform intervals, to obtain a large production of prints at the lowest cost .per print and with a low percentage of rejects, if any. It is well known that in the production of photoprin'ts, the drying of the prints is a time-consuming and costly operation. Various print-drying machines have been proposed previously; and where one such machine has given satisfactory speed of output, it has failed to give satisfac tory quality performance, and vice versa;

An important object of the invention is to provide a method and apparatus forrapidly, effectively and safely handling and drying ferro-t-ype prints.

One of the important objects, also, is to provide a method and apparatus for controlling the conditions of air temperature and move,- ment in the drying chamber ;;todry the prints uniformly, to dry these without robbing the emulsion of its elasticity, and at the same time to dry the prints quickly and without any tendency to flutter or otherwise disturb them as they are being dried.

Various other objects of theinvention will be pointed out or apparent, in, thecourse of the following description of the apparatus shown in the accompanying drawings and of the method as carried out with the aid: of such apparatus.

Referring to these -drawings,which show one form of apparatusv which may be em:- ployed according to the invention,

Fig. 1 is a side elevation thereof with the near side-wall removed;

Fig. 2 is a top horizontal section taken 011 line 2:-2 of Fig. 3

Fig. 3 is a transverse vertical section taken on line '33 of Fig. 2; V

Fig. 4; is a side elevation, on a reduced scale, and with the near side-wall broken away;

Fig. 5, is an enlarged fragmentary perspective View, showing an electrical synchronizing device;

Fig. 6 is an enlarged detailed View, showing a change-speed gear inside elevation, and a speed-reducing gear in section, such section being taken on the line 6-6 of Fig. 2;

Fig. 7 is an enlarged fragmentary view, showing said speed-reducing gear in end elevation, and also showing parts of feed-in rollers for a print carrier;

Fig. 8 is a View similar to Fig. 7, but showing in side'elevation the mounting means for said rollers at a point on the machine opposite such speed-reducing gear; and

Fig. 9 is a fragmentary perspective view on an enlarged scale, showing a portion. of a gravity'ejection means for a print carrier.

In the form of apparatus shown in these views, there is a columnar drying chamber,

through which horizontal-1y disposed print I carriers for the prints to'be dried pass downwardly during the drying operation. These carriers are, desirably, japanned metal rectangular plates each having spread on its upper surfaces a group of wet prints.

A plurality of such plates are shown at 10 in Fig. 3, each plate supported on a pair of L-ledges 11', carried by endless chains 12. The inner or facing vertical stretches of these chains mark the side walls of the drying chamber. Each chain passes over a sprocket 13 fast on an upper shaft 14 and a sprocket 15 fast on a shaft 16. y

The plates are of the width indicated in Fig. ,3, and of the same length as that of the shaft 30 of the roller.

thereon, are fed into the machine through a pair of feed-in rollers 21. The prints are dripping wet when applied as indicated at 22 in Fig. 1 to each plate, by the attendant grouping the prints on such plate'during op eration of the apparatus. This attendant stands on a platform 23, so as to have at about waist level a tank 24 containing a bath in which the prints are stored preparatory to being applied to the plates. Each plate, as prints are to be transferred thereto from the bath, is supported on an inclined rest 25 having bottom fingers 26; so that by the time a plate then on the rest 25 has been covered with prints, some excess liquid has been drained back into tank 24. Nevertheless, the prints are still. quite wet. However, the feedin rollers 21, which are preferably of soft rubber, also act as wringers relative to the prints as the plates pass through these rollers.

The rollers are of a familiar type wherein the upper roller is vertically adjustable at opposite ends by block and screw, as most clearly shown in Figs. 7 and 8. Thus the upper roller may be lifted above the lower roller when the machine is not in use; and during operation, the pressure between the rollers may be regulated as desired.

Referring to Figs. 2, 6 and 7, the lower roller 21 is power-driven by an electric motor 27 having fixed on its shaft 27 a worm 28 meshing with a worm-gear 29 fast on the This shaft 30 has also fixed thereon a Worm 31, meshing with a worm-gear 32 fast on a shaft 33. This shaft 33 runs along one side of the machine, as shown best in Figs. 2 and 6, and has an end portion thereof rotatable in the upper sockets of a pair of triple-socket brackets 34. Splined on the length of shaft 33 between these brackets is a spur-gear 35 having a familiar collar-and-fork connection, as indicated at 35, with a nut-traveller 36 on a screw 37 adapted to be operated by a handle 38; the nut-traveller having a depending portion carrying a collar 36 sleeving a guide-rod 34 riveted at opposite ends in the bottom sockets of brackets 34. Thus, the handle may be used when desired to shift the spur-gear 35 axially to cause its teeth to engage with a different circumferential series of teeth on a face-gear 39.

By the means just described, the speed of the parts driven by said face-gear 39 may be regulated, to hasten or slow down the length of the drying operation, as to accommodate the speed of the machine to various types of prints or to a particularly quick or a particularly slow attendant on the platform 23.

This change-speed face-gear 39 is fixed on a cross-shaft 40.

As shown best in Fig. 2, shaft 40 has fixed thereon bevel gears 41, each meshing with a bevel gear 42 on one of the two upper shafts 14 which have secured thereon the upper sprockets 13 for the chains 12.

Thus, the feed-in and wringer rollers 21, and also the chains 12, are driven simultaneously and continuously by the motor 27'; the speed of the chains is regulable relative to the speed of the rollers, but the rollers always run at higher speed than the chains; and the rollers rotate in the proper feed-in direction while the chains are both descending along their inner stretches to lower the ledges 11 between pairs of-which on different chains the print carrier plates 10 are supported.

The plates fed inby the rollers 21 are deposited with their print-covered surfaces uppermost, on three bands or belts 44. These belts, as shown in Figs. 1, 2 and 3, are supported at opposite ends on separate drums on two short cross-shafts, the forward one of which is power-driven intermittently by means now to be described.

This forward shaft, marked45 in Figs. 2 and 4, protrudes beyond the inner of the two fixed side-guards shown at 46 in Fig. 2; such guards being provided for the plates alight ing on and moving with the belts 44. On said protruding part of the shaft 45 is fixed a pulley 47, over which is passed a belt 48 passing also over the smaller pulley 49 of the two pulleys on a shaft 50, inside the casing. Over the larger pulley 51, passes a belt 52, which also passes over a pulley 53 on the shaft of a motor 53, suitably mounted in place, as on a cr0ss-bar indicated at 53" in Figs. 2 and 4.

This motor 53 is intermittently operated to drive the upper stretches of the belts 44 to the left in Fig. 2, for automatically transferring a plate on the belts 44 to a pair of ledges 11 on the two chains 12 as each such pair comes opposite said belts. In this connection, note Figs. 4 and 5; the latter showing end portions of a plurality of theledges 11 on a rising stretch of a chain 12. An armature for a normally open switch between electric wires 54, is shown as comprising a wipeplate 55 on the end of a leaf-spring 56 suitably anchored on an insulating block 57. These wires, are connected when the leafspring is elevated to touch the lower end ofa contact stud 58; and while the wires are thus connected, the motor 53 is energized. The parts are so arranged, that with the leafspring biassed to rest normally against a stoppin 59, an end of a ledge 11 engages and lifts the wipe-plate 55 to move the spring up to contact the stud 58, at the instant other ledges forming a pair on the two chains in the same horizontal plane arrive opposite the delivery end of belts 44. Motor 53 always operates a proper length of time to transporta plate on belts 44, opposite the ledges last mentioned, to deliver the plate onto said ledges; due to the design of the parts and particularly the degree of original overlap of the termittently delivered to the top pair of ledges of the chains 12, the inner stretches of thesechains continuously descend carrying with them a column of horizontally disposed plates, and as the lowermost ledges begin to travel around the lower sprockets 15, these plates are dropped free of the chains.

The plates thus dropped'fall onto an inclined discharge-frame having loose antifriction rollers 61 as will be seen best from a comparison of Fig. 9 with Figs. 2, 3 and 4. The lower or delivery end of this discharge-frame is opposite an opening 62 so located that the plates with the dried prints are finally delivered to a take-away pan 63 resting on floor 19.

,As a means for preventing face-whip of the inner stretches of chains 12, presserplates-may be provided as indicated in broken lines at 64 in Fig. 3; to insure that a plate 10 will securely rest on its ledges 11 during descent of the plate through the drying chamber, once a plate has been properly seatedon a pair of ledges. To insure a seating of all the plates on their ledges so that one shall be vertically above another, a suitable stop means adjacent the remote ends of each pair of ledges as such pair comes opposite the belts 44 is provided. Such stop means may, for instance, be carried by each of the ledges, as indicated at11 in Fig. 2, or may be carried by some fixed part of themachine as a plate 65.

Referring now to the means for circulating and heating the drying air relative to the print transporting means, it will be noted, that when the hood-cover H is applied, and the inspection doors 66 are closed, circulation chambers, marked C in Fig. 2, are provided at opposite sidesof the ath of travel of the plates in columnar re ation. Also, if desired, and this is now recommended, the inspection openings shown at 67 in Fig. 4 are closed by suitable sheet metal structures (not shown), during operation of the machine; and then the drying chamber itself is closed on both sides from top to bottom.

The only other openings inthe apparatus, with the exception of intake openings 68 for upper and lower fans 69 in each ofthe two chambers C, are the bottom openings 62 and a top opening 70 through which is protruded the flared end of the structure carrying the side-guards 46.

These fans 69, which are preferably arranged in pairs in balanced'relation on opposite sides of the drying chamber, induce a circulation of air inside the casing which I find maintains warm air in the drying chamber and over the printson thedescending plates, without localized agitations and so without fluttering the prints or blowing them loose or otherwise injuring them. In order toinduce the minimum of local air agitation, two inclined baffles are desirably provided, in the present case as indicated at 71, inF-ig. 1. These baflies, to clarify the drawing, are not shown in Fig. 2,but they extend across the entire machine. The upper ends of said baffles have secured thereto the upperends of a pair of screens 7 2. These screens are intended as extra insurance against a too-quicklydried print being blown ordrawninto a flame.

Air heating means served by baflies 73, similar to but narrower than the baliles 71, comprise. elongated gas burners as indicated at 74, gas being supplied to the burners through a pipe 7 5 regulated by cocks 76.

The placing of the heating means near the bottoms of the, chambers C is preferred, be cause then there is a constant movement in both chambers of heated air, further tending to preclude localized air agitation. These rising columns of heated air are approxi mately balanced as to temperature and pressure at any point along the height of the dry. ing chamber. Cool outside air, however, is being drawn in, first at the level of the lower pair of fans 69, and, next, at the level of the upper pair of fans 69. Thus, the rising columns of; air in the chambers O are at a higher temperature as the plates 10 approach the discharge-frame 60, and are of less and less temperature in regard to the plates nearer: and nearer the belts 44. Accordingly, a plate 10 travels down the length of the drying chamber to dry its prints, not only gently so far as air flusters are concerned,but gently so far as heat application is concerned, since as the plate travels down further and further the prints thereon are subjected to the drying action of air which is of a higher and higher temperature.

It will be appreciated that an important feature of the invention is involved in this method. of controlling the air conditions in the drying chamber, as to temperature and movement.

In the use of previous machines, which machines, I am aware, have attempted to employ fans, blowers and the like, for inducing air circulation, and also heating means, for varying the temperature of the circulating air, apparently two chief requisites among others havenot been appreciated. One of these main requirements is that the heat must be so regulated as to increase the moisture absorptive properties of the air to the maximum and yet not rob the emulsion of its elasticity. At the same time, it must be kept in mind that the air-circulating and air-heating means must be so comblned as to avold creating undesirable localized air-currentsand swirls in the vicinity of the prints being dried.

I prefer to subject the air going into the casing, through the openings 68, to a preliminary treatment involving first a heating, next a sharp cooling to condense out moisture and nexta reheating to raise the dew point. Whether or not this preliminary treatment is given to the air drawn in under pressure by the fans 69, it will be noted, from the locations and dimensions of said openings an dfans and the other dimensional features of the illustrative apparatus shown, that I provide an improved method of drying prints which, While avoiding the previous troubles noted, has several lmportant advantages. Thus, I may employ a drying-chamber so shaped, in the present case columnar, that the prints may be moved through the cham ber in compact relation yet with all the prints spaced and with one entire face of each print always exposed to the drying air. To this end, I may employ substantially rigid plates 10 on which the prints are spread as above. The use of these plates or similarly rigid sup.- ports, in turn permits the use of chains 12, or belts or the like as equivalents; with the chains arranged in pairs so that pairs of coacting ledges 11 or the like may be mounted on the chains to provide a line of travelling racks which are automatically readjusted to release a plate at one end of said line and automatically re-established as plate-carry ing racks at the opposite end of said line. At the same time, a columnar drying chamber is conveniently provided, bounded on two of its sides by the planes of the ledges of the platecarrying racks. As a result, a practical casing structure is made possible, wherein columnar chambers C of substantially the same size are located on opposite sides of the drying chamber, beyond the ledges forming the racks; and in these chambers may be disposed openings 68, fans 69, heating means 74 and, if desired, bafiies like those indicated at 71 and 73, for operation as described.

As will be seen from what has been said, the present invention, more broadly, provides a method of controlling the air and pressure conditions relative to a drying chamber, and a method the carrying out of which is particularly facilitated by the employment of an apparatus such as the one shown in the drawings, having marked advantages of simplicity and ruggedness, and reliability and speed of operation in handling the prints, not only during their passage through the drying chamber, but preparatory and subsequent to such passage. Such method involved maintaining the air in the chamber substantially at uniform pressure all over or with such slight local variations as to avoid, not only any possible fluttering, dancing or other undesirable and unintended movements of the prints while in the chamber, but to insure carried out by maintaining substantially balanced air pressures on opposite sides of the path of travel of the drying prints, at different points along said path.

Preferably, also, the method involves controlling the air temperatures as well as the air pressure conditions relative to the drying chamber, by maintaining the aforesaid balanced air pressures, while circulating the air in similarly moving columns on opposite sides of the drying chamber, and while heating these air circulations in such manner that the balanced pressures will not be noticeably disturbed. When the air columns on opposite sides of the air chamber are ascending, as is preferred, and the heating means are located near the bottoms of the columns, as is preferred, the columns are of different temperatures at different levels and are of less temperature at the higher levels. Accordingly, where the drying chamber is vertical, as shown and preferred, and the prints are moved downwardly through said chamber, the prints as they pass through the chamber will be dried by being progressively subjected'to strata of heated relatively quiescent air of higher and higher temperatures.

Perfectly balanced pressures on opposite sides of the drying chamber, at all points along the length of the path of travel of the prints, are not believed necessary. As the invention is preferably carried out, preferably by the use of plates 10 each carrying a plurality of prints, the opposing pressures across such path at any point along the length thereof, are such as to give substantially uniform pressure and temperature conditions for the whole plate area at that point. Then, at said point, each print on each plate passing the same, will dry approximately if not precisely to the same extent. Also, the opposing pressures need not be the same at different points along said path, particularly if the pressures at the different points, whatever they are, be maintained continuously; because then, obviously, each group of prints on a plate would be subjected tothe same succession of drying zones, and all prints, on the same ED CldOII different plates, will be uniformly rie It should be borne in mindthat the drawings and the foregoing description merely indicate typical embodiments of features which may take many different forms. The appended claims are to be construed as extending to all such forms or modifications as fall within a broad. interpretation of the terms used therein.

I claim:

1. In print drying apparatus, in c'ombina tion, a drying chamber, means therein adapted to support a plurality of prints to be dried in spaced relation, and means for introducing prints into said chamber including a mechanically operated moisture removing and feeding plates in horizontal position in space in device for the prints and an electrically operated device for positioning the fed-in prints on said supporting means.

2. A device of the character described, in combination, a drying chamber, means for removing the surplus water from print supporting plates and for feeding them into said drier and assembling them in a vertical pile in spaced relation, means for moving said pile downwardly through said drying chamber, means for removing plates from the bottom of the pile, means for circulating air through the space between the plates, and means for diffusing said current of air as it enters the space between the plates.

3Q In a device of the character described, in combination, a drying chamber comprising an outer casing, means within said casing for supporting a plurality of print supportrelation and for moving said plates vertically, fans beyond the periphery of said plates for circulating air between successive plates said fans being disposed so that prints on said plates will not be disturbed by circulation of air, means immediately adjacent to the peripheries of the plates for diffusing the air introduced and heating means below said fans.

4. In a print drier in combination a drying chamber, a plurality of plate supports within said chamber, means for moving said supports through said chamber in spaced relation, means for blowing air directly upon said plates during the first portion of their pasing chamber, means for feeding print supporting plates to said chamber, a plurality of plate supports adapted to receive plates from said feeding means, means for moving said supports downwardly through said drying chamber, means for removing the plates from the supports at the bottom of said chamber, and means situated at the side of said supports for blowing air inwardly in a plurality of directions over said plates to substantially equalize the air pressure over each of said plates.

8. In a print drier in combination a drying chamber, means for feeding print supporting plates to said chamber, a plurality of plate supports adapted to receive plates from said feeding means, means for moving said supports downwardly through said drying chamber, means for removing the plates from the 1 supports at the bottom of said chamber, means situated at the side of said supports for blowing air inwardly and in opposite directions over said plates and means for diffusing said air during the lower portion of the travel of the plates. I

ARTHUR J. CUNNINGHAM.

sage through the drier and means for blowing air upon said plates through a diffusing means during the latter portion of their travel through the drier, said means for blowing air being disposed so that the air pressure at any level of the drying chamber is substantially uniform.

5. In a print drier in combination a drying chamber, a plurality of plate supports within said chamber, means for moving said supports through said chamber in spaced relation, oppositely disposed means for introducing air at the side of said plate supports at points distributed along the pathway of movement and diffusing screens for breaking up the air currents passing to the plates during the last portion of their travel.

6. In a print drier in combination a drying chamber, a plurality of plate supports within said chamber, means for moving said supports through said chamber in spaced relation, means for introducing air at the side of said plate supports at points distributed along the pathway of movement so that the air pressure at a certain level within the chamber will be uniform, diffusing screens for breaking up the air currents passing to the plates during the last portion of their travel and means for heating said air.

'8'. In a print drier in combination a dry- 

